Piero Savarino

Reactivity and effects of cyclodextrins in textile dyeing

Abstract Four- to 10-fold improvement of colour uniformity and minor changes of colour yield have been found upon dyeing Nylon 66 and microfiber Nylon 6 fabrics in the presence of cyclodextrin compared to dyeing without it. 1 H NMR data supported the role of cyclodextrin as dye complexing agent. Product quality, however, was also dependent on fabric nature, since for conventional Nylon 6, color uniformity was not improved by the presence of cyclodextrin systems.

Use of biosurfactants from urban wastes compost in textile dyeing and soil remediation

A compost isolated humic acid-like (cHAL) material was pointed out in previous work for its potential as auxiliary in chemical technology. Its potential is based on its relatively low 0.4gL(-1) critical micellar concentration (cmc) in water, which enables cHAL to enhance the water solubility of hydrophobic substances, like phenanthrene, when used at higher concentrations than 0.4gL(-1). This material could be obtained from a 1:1 v/v mixture of municipal solid and lignocellulosic wastes composted for 15 days. The compost, containing 69.3% volatile solids, 39.6% total organic C and 21C/N ratio, was extracted for 24h at 65 degrees C under N2 with aqueous 0.1molL(-1) NaOH and 0.1molL(-1) Na4P2O7, and the solution was acidified to separate the precipitated cHAL in 12% yield from soluble carbohydrates and other humic and non-humic substances. In this work two typical applications of surfactants, i.e., textile dyeing (TD) and soil remediation by washing (SW), were chosen as grounds for testing the performance of the cHAL biosurfactant against the one of sodium dodecylsulfate (SDS), which is a well established commercial synthetic surfactant. The TD trials were carried out with nylon 6 microfiber and a water insoluble dye, while the SW tests were performed with two soils contaminated by polycyclic aromatic hydrocarbons (PAH) for several decades. Performances were rated in the TD experiments based on the fabric colour intensity (DeltaE) and uniformity (sigmaDeltaE), and in the SW experiments based on the total hydrocarbons concentration (CWPAH) and on the residual surfactant (Cre) concentrations in the washing solution equilibrated with the contaminated soils. The results show that both cHAL and SDS exhibit enhanced performance when applied above their cmc values. However, while in the TD case a significant performance effect was observed at the surfactants cmc value, in the SW case the required surfactants concentration values were equivalent to 25-125xcmc for cHAL and to 4-22xcmc for SDS. The vis-a-vis comparison of the two surfactants gave the following results: in the TD case the cHAL biosurfactant at 0.4gL(-1) yields good colour intensity and equal colour uniformity as SDS at 5gL(-1), in the SW case cHAL was found to enhance CWPAH by a factor of 2-4 relative to SDS with one soil, whereas with the other soil the two surfactants behaved similarly. The Cre data, however, showed that both soils absorbed by far more SDS (68-95%) than cHAL (12-54%). The results point out intriguing technological and environmental perspectives deriving from the use of compost isolated biosurfactants in the place of synthetic surfactants.

Acid soluble bio-organic substances isolated from urban bio-waste. Chemical composition and properties of products

As previous work proposed commercial expectations for soluble bio-organic substances (SBO) isolated from compost of urban food, gardening and park trimming residues as chemical auxiliaries, nine urban bio-wastes (BW) treated by aerobic and anaerobic digestion for 0-360 days were used to extract SBO and investigate source variability effects on product chemical composition and properties. The bio-wastes were collected over a 13732 km(2) area populated by 2.9 millions from 565 municipalities. The SBO were characterized by their content of different C types and functional groups and by their distribution coefficient (K(PEGW)) between polyethylene glycol and water. A significant linear correlation was found between K(PEGW) and the lipophilic/hydrophilic C ratio. The investigated SBO exhibited up to sixfold change of K(PEGW) demonstrating that BW available from densely populated urban areas are an interesting exploitable source of a wide variety of potential products for the chemical market.

Aqueous micellar solutions of some N-alkylnicotinamide and N-alkylpyridinium halide surfactants: Apparent and partial molar enthalpies

In order to acquire thermodynamic data for aqueous solutions of functionalized surfactants, and to study the effect of the amidic group in the polar head and of the counterion, the enthalpies of dilution at 25°C of N-alkylnieotinamide chlorides (alkyl chain length 7, 9 or 10 carbon atoms), N-alkylpyridinium chlorides (alkyl chain length 8, 10 or 12 carbon atoms), N-octylpyridinium bromide and N-decylpyridinium bromide have been measured by means of an LKB 2107 flow microcalorimeter. From the experimental data, apparent and partial molar relative enthalpies as a function of the molality of the surfactant have been derived. The amidic group in the nicotinamide compounds greatly enhances the hydrophobicity relative to the pyridinium compounds. For cationic surfactants with the same alkyl chain, the trends of the molar enthalpies vs. concentration can be explained in terms of charge localization on the polar head. For the compounds under investigation, enthalpic data are not able to show phase transitions in the micellar region, but they confirm the role of the counterion in the energetics of micellar solution. The thermodynamic functions of micellization have been evaluated on the basis of the pseudo-phase transition model by graphical extrapolation.

Biosurfactants from Urban Green Waste

From waste came forth surfactants: Humic acid like substances isolated from 0-60 day-old compost display excellent surface activity and solvent properties. These biosurfactants were used to solubilize a dye in water below and above their critical micellar concentration. The biosurfactant unimers appear to have higher dye-solubilizing power than the corresponding micelles.Humic acid like substances isolated from compost show potential as chemical auxiliaries. In the present study, three surfactant samples were obtained from green waste composted for 0-60 days to assess aging effects of the source on the properties of the products. The surface activity, dye solubility enhancement, and chemical nature of these substances were compared. No differences in performance were established among the samples. They lower water surface tension and enhance the dye solubility upon increasing their concentration. However, the ratio of soluble dye to added surfactant is higher in the premicellar than in the postmicellar concentration region. Structural investigations indicated the humic acid like substances to be amphiphiles with molecular weights in the range of 1-3 x 10(5) g mol(-1). The surfactant samples were also compared to sodium dodecylbenzenesulfonate, polyacrylic acid, and soil and water humic substances. The results encourage the application of compost as a source of low-cost biosurfactant.

Disperse and cationic dyes from 2-(o, m, p-Aminophenyl)oxazolo [4,5-b]pyridine

Abstract 2-( o,m,p -Aminophenyl)oxazolo[4,5-b]pyridines were diazotized and coupled with N,N-disubstituted anilines, giving monoazo dyes suitable for polyamide fabrics. Some of the dyes were quaternized to give cationic dyes for acrylic fibres. The colour of dyed materials was assessed in terms of tristimulus colorimetry. Electronic spectra of the amines and NMR spectra of the cationic dyes are briefly discussed.

Behavior and Properties in Aqueous Solution of Biopolymers Isolated from Urban Refuse

Acid soluble biopolymeric substances (SBP) were isolated from different urban biowastes comprised of a range of materials available from metropolitan areas. These biowastes provided products with a chemical nature and solubility properties changing over a wide range and, thus, allowed to assess the effect of the variability of the chemical nature on molecular conformation and surface activity in water solution. For this scope, the SBP were characterized for chemical composition and molecular weight (MW) by microanalysis, potentiometric titration, (13)C NMR spectroscopy, and size exclusion chromatography (SEC) coupled with an online multiangle light scattering (MALS) detector. These materials were found to have 67-463 kg mol(-1) MW and 6-53 polydispersity index and to contain carboxylic acid and phenol groups bonded to aromatic and aliphatic C chains. An empirical parameter (LH) was calculated for use as an index of the lipophilic/hydrophilic C atoms ratio. The products solubility properties in solvents of different polarity, surface activity, power to enhance the water solubility of hydrophobic compounds, and particle size in water solution were also investigated by measurements of the products partition coefficient between polyethylene glycol and water (KPEGW) and of air-water surface tension (γ), water-hexane interfacial tension (IFT), disperse red orange dye solubility (DS), and dynamic light scattering (DLS) versus added SBP concentration (Cs). The results indicate that LH correlates well with KPEGW and with the products surface activity properties. Both γ and DS are shown to depend on Cs, although in opposite ways, that is, higher Cs values yield lower γ and higher DS values. Both DS-Cs and γ-Cs plots showed a significant slope change at approximately the same 1.8-2.5 g L(-1) Cs value. This suggested a change of molecular conformation taking place at the above Cs values. Hydrodynamic diameter values for SBP in solution at Cs ≤ 10 g L(-1) were found to range from 130 to 300 nm, consistent with their macromolecular nature. The DLS coupled to the γ data were consistent with molecules at the water-air interphase and in the bulk water phase having different conformations, but not significantly different molecular sizes. Molecular aggregates more likely form at 50-100 g L(-1) Cs. The results confirm that urban biowastes are a sustainable source of biobased products that may have real commercial perspectives.

Quantitative structure-property relationships study of azo dyes using partial least Squares analysis in latent variables (PLS)

Abstract The light, washing, alkali and perspiration fastness of a series of azo dyes are analysed as a function of physicochemical substituent descriptors by the PLS method. The analysis permits relation of the fastness properties to the structural features and the development of a model which can be used to predict the fastness of new dyes of the same series.

Polyalkylphenyl-sulphonic acid with acid groups of variable strength from compost

The insoluble organic fraction (humin-like material, HLM) from rice hull-dairy cattle compost is well converted into water soluble HLM-sulphonate by reaction in liquid SO3. Microanalytical, potentiometric, molecular weight, and NMR data are consistent with a highly homogeneous polymeric arylsulphonate having 4000 Da MW, 1.3 sulphonic groups per aromatic ring and significant content of carboxylic and phenolic groups. By comparison with structure-property relationships for commercial lignosulphonates derived from the pulp and paper industry, the above arylsulphonate is likely to be a candidate at a variety of applications in the chemical industry and in agriculture. Therefore, sulphonation is a means for upgrading composts HLM to the same uses as for commercial lignosulphonates.

Preconcentration of aniline derivatives from aqueous solutions using micellar-enhanced ultrafiltration

The preconcentration of aniline derivatives present in aqueous solutions containing ionic surfactants was performed using the micellar-enhanced ultrafiltration technique. The efficiency of the analyte recovery in the surfactant-rich retentate was significantly improved by exploiting the electrostatic, hydrophobic and specific interactions between the aggregates and the solute molecules. By working at low pH, in the presence of anionic micelles, the quantitative retention of amines having different substituent groups can be achieved. The enriched sample can be analysed directly using high-performance liquid chromatography.